Form Fill Seal Versus Premade Bag Machines

The Two Machines In One Paragraph

A form fill seal machine takes a roll of film, forms it into a bag, fills it, seals it and cuts it off, all in one pass. A premade bag machine takes a finished bag from a magazine, opens it, fills it and seals the top. The first makes the bag. The second buys it.

Cost Per Pack

Roll film wins on cost, usually by a wide margin. You are buying a commodity by the kilogram rather than a converted product by the unit. On a high-volume industrial pack this difference alone can justify the machine within a year.

Premade bags cost more per unit, and they also carry an inventory cost: every bag size and every printed design is a separate stock item with a minimum order quantity.

Speed

Form fill seal is generally faster on small packs. Published speeds on our P-series run to 40 to 70 bags a minute in the 5 g to 200 g range. Premade bag machines on the GP-series are published at 20 to 50 bags a minute.

The gap closes as the pack gets bigger, because at 2 kg the limiting factor is filling time rather than bag handling.

Pack Presentation

This is where premade wins and it is not close. Stand-up pouches, zippers, spouts, matte finishes, shaped cuts and eight-side seals are all off the shelf for a premade bag and either impossible or expensive on a formed bag.

If the pack has to sell the product on a supermarket shelf, this usually decides the argument on its own.

Changeover

A form fill seal machine changes bag size by changing the forming shoulder and calling up a stored recipe. A premade bag machine changes by loading a different bag into the magazine and adjusting the grippers.

Premade is generally quicker for a short run of a different size. Formed film is quicker if you are running the same size all week and only changing the product.

Sensitivity To Supplier Quality

A form fill seal machine is sensitive to film quality: thickness variation and sealing layer consistency show up as leaking seals. A premade bag machine is sensitive to bag dimensional consistency: a batch of bags a millimetre out of tolerance will cause pick failures all shift.

Both problems are supplier problems rather than machine problems, and both are solved by writing a tolerance into your purchase specification.

A Practical Rule

If the pack is industrial, high volume and the customer is another factory, choose form fill seal. If the pack is retail, mid volume and the customer is a shopper, choose premade. If you are in between, run the numbers on cost per pack including labour and giveaway, and remember that the machine is a smaller part of the decision than the packaging bill is.